I think i would stay away from wrasse in a nano. I have a blue figi chromi, royal gramma and a sleeper head goby. They live fine in harmony. The Royal gramma can get grumpy at times. He just opens his mouth really big, like he is yelling, and goes about his business. I have never seen him attack anything. He chased the sleeper goby around when we first put him in, but they got along eventually.
Rad- Maroons are going to get fairly big, too big for a Nano imo. The females get pretty large.
You could also look into getting a clown goby. They are pretty cool and relatively inexspensive.